Messages from the US FAA Air Traffic Control System Command Center (ATCSCC) include several important types of information:

  • Airport and gate hold delays

  • System administrative messages

  • North Atlantic and North Pacific track information

File Description

Messages issued by the Air Traffic Control System Command Center are captured and distributed in files using the following naming convention:
NDnn.ALP
Where:
nn = sequence number up to 99, wraps to 00

ATC Message Format

Each file contains a header followed by the ATCSCC message. The information below describes the layout of the file:

Where:

The first 2 lines represent the hex offset from the start of the record. (OFFSET)
Lines 3-5 represents the layout of the record with the following conventions: (LAYOUT)

Binary Markers – each represents 1 binary character.

  • SOH = 0x01 = Start of Header

  • STX = 0x02 = Start of Text

  • ETX = 0x03 = End of Text

Data:

  • n = fixed length numeric data

  • a = fixed length alphanumeric data

  • v = variable length alphanumeric data

All other characters represent the actual ASCII character found in the file.

NOTE: Spaces matter!

The sixth line identifies what each of the data parts represent. (DATA)

DDHHMM – 6 digit number representing the day, hour and minute as 2 digits each
Message Text [MSG TEXT] – message text as a variable length string

Category: FAQ's